Strengthening of poles

ABSTRACT

A bridging beam for bridging a weakened area of a pole to reinstate the pole. The beam includes a sleeve for abutting the external surface of the pole on an inner surface of the sleeve and an external brace extending outwardly from an outer surface of the sleeve. The brace is constructed to brace the sleeve in radial and tangential directions relative to the sleeve. The brace is formed as an elongate tubular box section.

FIELD OF THE INVENTION

The present invention relates to the strengthening of poles and, moreparticularly has application to the reinstatement of poles particularlydamaged poles.

BACKGROUND OF THE INVENTION

The present invention can be applied to poles used by utilities forcarrying telecommunications lines, electric power lines and the like. Itis to be appreciated however that the invention has application to otherforms of poles including pylons, stumps, flagpoles, mooring posts andthe like.

Poles of the type to which this invention has particular application aretypically wooden poles and it is well known that a wooden pole is mostvulnerable to rot, decay or similar degradation at about ground levelincluding the area from slightly above to slightly below the ground lineof a standing pole. This is the area in which rot generally begins andas the decay spreads the pole is weakened. If a utility pole shouldfail, there may be serious disruption to telecommunications and/or powersupply. Further, the sudden failure of a pole is a risk which linesmanworking on such poles face regularly. In addition to the risks of afaulty pole falling and bringing down not only the lines but alsolinesmen with it, there are risks to passers-by and neighbouringbuildings or other structures. Similar dangers and inconvenience mayresult from the failure of poles used in other applications.

The reinstatement of damaged poles is accordingly an importantconsideration. However it can be difficult to properly identify damageto a pole. Accordingly it may sometimes be necessary or advisable toprovide added strength to a sound pole. The terms reinstate andreinstatement are accordingly used herein to refer to the addition ofstrength to a pole irrespective of whether the pole has been previouslydamaged and/or weakened in any way.

When a pole carrying transmission lines fails, the pole is generallysupported by the overhead lines in the longitudinal direction of thelines. Accordingly, it is more typical for a utility pole which fails tofall sideways, ie. transversely of the overhead transmission lines.

There has been a number of proposals for providing support members foradding strength to a pole. However, the previously known members sufferthe disadvantage that the added strength is typically providedsubstantially normally to the support member and limited support isprovided tangentially thereto. Accordingly, in order to providesufficient support to restrain a failed pole from falling transverselyof an overhead transmission line, it is necessary for the prior artsupport members to be placed beside the pole rather than betweenneighbouring poles.

In urban areas, underground services which may include gas, water,power, stormwater and other services are typically located in aneasement which runs substantially beneath and parallel to the overheadtransmission lines. Accordingly other services may run besidetransmission poles but generally are not placed between neighbouringpoles. Therefore, there is an added risk in the prior art arrangementsthat installation of such prior art support members beside a pole ratherthan between neighbouring poles may cause disruption to undergroundservices.

Moreover, prevailing winds can play a significant role in the directionof fall of a failed pole and it is not always possible to predictaccurately the direction from which the fatal wind gust will appear andto orient a support member accordingly. Furthermore in the event of asingle conductor failing a power pole can be subjected to a twistingmoment about its longitudinal axis.

Accordingly, there exists a need for the capacity to reinstate poles ina manner which provides improved support in both the normal andtangential directions relative to the support member, ie. longitudinallyand transversely with respect to the lines carried by a transmissionpole as well as resistance to twisting about the longitudinal axis ofthe pole.

SUMMARY OF THE INVENTION

The present invention accordingly provides in one preferred embodiment abridging beam for bridging a weakened area of a pole to reinstate thepole including a sleeve for abutting the external surface of the pole onan inner surface of said sleeve and an external brace extendingoutwardly from an outer surface of said sleeve portion, said brace beingconstructed to brace the sleeve in radial and tangential directionsrelative to this sleeve. Resistance to twisting about the longitudinalaxis may also be provided by the brace. Connection means may be providedfor connecting the beam to a pole being resinstate.

A bridging beam provided by the present invention is preferably suitablefor being driven into the ground in a substantially vertical orientationimmediately beside the pole to be reinstated. The bridging beam may beformed from steel or other material of suitable strength and otherproperties. Preferably all components of a beam according to the presentinvention are adapted to be galvanised or otherwise treated against theadverse effects of weathering and soil immersion.

A beam according to the present invention may include a sledge end tofacilitate driving the beam into the ground immediately adjacent thepole being reinstated. The sledge end may include a curved or otherwiseupturned portion immediately adjacent the lower point of the beam inuse.

Most preferably, a beam according to the present invention is ofsubstantially constant cross section throughout the major portion of itslength. In particular, it is preferred that a bridging beam according tothe present invention does not taper for a significant portion of itslength as we have found that a greater surface area of sleeve portion incontact with the pole provides improved friction against the pole andthe surrounding soil and hence improved reinstatement capabilities.

A sleeve of a bridging beam according to the present invention ispreferably formed from a single piece of material. The sleeve may besubstantially arcuate in cross section. However, sleeves of other crosssectional shapes including substantially channel shaped, angled andpolygonal shaped sections among others are also envisaged within thescope of the present invention. Most preferably the shape of the innersurface of the sleeve is such as to be complementary to the shape of thecircumference of the pole being reinstated.

A sleeve according to the present invention is preferably aperturedwhereby to enable connection means to pass through the sleeve and intothe pole being reinstated as described in greater detail below.

A sleeve according to the present invention may be curved or otherwiseshaped at the lower most extremity in use whereby to facilitate drivingthe beam into the soil immediately surrounding the pole undergoingreinstatement. A cambered end portion or sledge end is particularlypreferred.

A sleeve according to the present invention preferably spans less than50% of the circumference of the pole. Preferably the sleeve spans morethan 10% of the circumference of the pole and most preferably betweenabout 20% and about 40% of the circumference of the pole undergoingreinstatement. It will be appreciated therefore that the shape and sizeof a sleeve provided in accordance with the present invention may varysubstantially depending upon the shape and size of the pole undergoingreinstatement. Irrespective of shape and size the sleeve preferablycomprises a unitary member which carries the other components providedin accordance with the present invention.

The outer marginal edges of a sleeve according to the present inventionare preferably substantially vertical in use. According to one preferredembodiment of the invention a gusset is provided along at least aportion of either or both outer marginal edges of the sleeve. The gussetmay be in the form of an extension of the outer edge which preferablyprojects outwardly from the pole. Most preferably the gusset is formedintegrally with the sleeve.

A gusset according to the present invention may extend substantiallyalong the length of a sleeve or, more preferably is of a sufficientlength of bridge the decayed area of a pole undergoing reinstatement. Wehave found that it is generally sufficient for a gusset to extend overat least 10% of the vertical extent of the sleeve, preferably between10% and 40% and most preferably between 10 and 25% of the overall lengthof a sleeve according to the present invention.

A gusset provided according to the present invention may extendsubstantially normally the plane of the sleeve at the join between thegusset and the sleeve or may extend outwardly at a more shallow anglefrom the outer marginal edge of the sleeve.

A sleeve according to the present invention also carries a braceextending outwardly from the outer surface of the sleeve. The brace maybe in the form of an extended channel mounted outwardly of the sleeve.The brace and sleeve may be formed integrally with one another, however,for ease of manufacture it is presently preferred that the brace andsleeve be initially formed as two separate members and that the brace besubsequently permanently mounted on the sleeve such as be welding orother suitable mounting means. The brace is intended to provideadditional stability to the sleeve and hence to the reinstated pole. Theconstruction and arrangement is preferably such that the brace impartsadded stability to the sleeve in a direction tangentially to the sleevein the area of the brace, ie. transversely of the brace as well asnormally to the sleeve in the area of the brace, ie. radially of thepole.

The brace is typically an elongated member. A brace according to thepresent invention is preferably formed as a unitary member but mayinclude a number of brace members joined to one another. A braceaccording to the present invention is preferably channel shaped and maybe in the form of a box channel or a U-shaped channel although otherforms of channel shape are also envisaged within the present invention.

The brace may form an elongate tubular member when joined to the sleeve.The outline of the elongate tubular member need not be substantiallycircular. Other cross-sectional shapes including generally semioval,semicircular, box, triangular or polygonal cross sections or acombination of such cross sections are all invisaged within the scope ofthe present invention.

A brace according to the present invention preferably includes a pair ofarms or other elements whereby the brace may be mounted on the othersurface of the sleeve at two spaces locations. Between these attachmentlocations the sleeve portion acts as a spreader for the brace therebyacting to maintain the integrity of the brace under load. When the braceis a channel shaped member the spreader and the brace effectively form abox section providing additional strength to the bridging beam providedin accordance with the present invention in both the tangential andnormal directions. The box section can also provide strength to resisttwisting about the longitudinal axis of the pole.

In accordance with the present invention the bridging beam is preferablyconnected to the pole by connecting means. The connecting means may bein the form of a threaded connector extending through the pole. Thethreaded connector may be in the form of a bolt having a head at one endand a nut or similar fastener at the other. Preferably the fastener canbe progressively tightened to fasten the connector in position.

The connector may extend directly between two sleeve portions accordingto the present invention.

In an alternative arrangement it is only necessary to use a singlesleeve portion according to the invention. In this arrangement a backingplate is preferably provided to facilitate the mounting of one end ofthe connector whereby to spread the load exerted by the connector overthe outer surface of the pole.

While it is convenient to hereinafter describe the connection means withreference to a connector extending between a sleeve portion of onebridging beam according to the present invention and a backing plate, itis to be appreciated that the backing plate may in fact be replaced by asecond sleeve portion to perform the same function in relation to thelocation of the connection means.

A backing plate is preferably an enlarged plate which is apertured toreceive an end of a connector according to the present invention. Thesize and shape of a backing plate may be varied as known in the art witha view to spreading the load exerted by the connector over a greatersurface area to reduce the prospect of local damage to the wood fibersof the pole and also to provide additional strength.

A connector according to the present invention preferably extendssubstantially across the centre of the pole and may accordingly form adiameter for a circular pole. It may be appreciated however that inpractice the question of whether a connector passes precisely throughthe centre of a pole is not altogether important and a connector mayaccordingly be installed to extend across a pole slightly to one side ofthe centre point without departing from the spirit or ambit of theinvention. Similarly, in the case of some irregular poles, it may be noteven be possible to locate a centre.

When a hole is drilled across a pole to receive a connector according tothe present invention, this necessarily removes a portion of the timberof the pole which may not only further weaken the pole but may result innew sites for moisture and other penetrations of the wood fibres whichmay provide new sites for decay to originate. This is particularly socloser to the surface of the pole.

We have now found that it is preferable for the outer extremities of aconnector according to the present invention to be countersunk into thepole. We have found such countersinking to be most preferable when aconnector end is mounted on a sleeve portion but of lesser importancewhere a connector end is mounted on a backing plate. The countersinkhole is preferably substantially concentric with the central boreextending through the pole for receiving the connector. The countersinkhole is preferably substantially frusto-conical in shape. The broaderbase of a coned countersink hole preferably substantially abuts theouter surface of the pole.

Most preferably the shape and dimension of the countersink hole providedin a pole is complementary to the shape and dimension of an end capwhich may be provided to receive and mount either or both ends of aconnector. An end cap may be inserted into the countersink hole. An endcap according to the present invention preferably contains a centralbore which in use is aligned substantially with the central boreextending through the pole. An end cap is preferably substantiallyfrusto-conical in shape.

The end cap is preferably shaped to provide a seat for the head of aconnector and the nut or fastener of a connector according to thepresent invention. Most preferably an end cap according to the presentinvention has an outwardly extending lip which may be arranged to extendover the marginal edges surrounding an aperture in the sleeve portion ora backing plate. A shank portion may depend from the outwardly extendinglip of a cap whereby to pass through the sleeve portion. The shankportion may merge with the frusto-conical end portion.

We have found that this frusto-conical end portion of a cap according tothe present invention is of particular advantage in that a protectivematerial such as a boron/fluoride based preservative cream may beinserted into the countersink hole prior to assembly of the connectionmeans according to the present invention, in which case the lighteningof the connection means will result in the preservative cream beingurged into the wood fibres of the pole. In this way the newly exposededges of the countersink hole may be protected against the effect ofweather and the likelihood of acting as fresh sites for decay of thepole. The cream or other preservative provided may also act as amoisture barrier to resist moisture permeating into the interior of thepole whereby to act as a further form of degradation within the centralbore.

In one particularly preferred arrangement an end cap according to thepresent invention may be threaded so that a separate nut is not requiredand the end cap may itself act as a fastener. In this arrangement theexternal bore of the end cap may be hexagonal or otherwise shaped toreceive a fastening tool of complementary shape whereby to tighten theend cap on the threaded portion of the connector. Such a hexagonal orother shaped bore may also be useful for retaining the head of aconnector in accordance with the present invention to facilitatetightening of the connection means as will be appreciated by thoseskilled in the art.

A brace in accordance with the present invention preferably does notextend to the upper extremity of the sleeve portion. In this way aportion at the upper end (in use) of the sleeve portion may be free ofbrace and this unbraced sleeve portion may be suitable for receivingstrapping which may pass around the pole being reinstated. Where a pairof bridging beams in installed by strapping preferably binds theunbraced sleeve portion of each beam. Where only one beam is employed toreinstate a pole a backing plate may be provided against the outersurface of the pole to receive the strapping and spread the load exertedthereby over a broader area. Such a backing plate is optionallyapertured to also received a portion of the connecting means connectingthe beam to the pole.

The strapping is preferably stainless steel or other material ofsuitable strength. Various means of securing heavy duty strapping aroundthe unbraced sleeve portion of one or more bridging beams according tothe present invention are currently known in the art. The strapping ofthe unbraced sleeve portions may provide a form of socket at the upperend of a bridging beam according to the present invention. The socketmay further strengthen the pole at the upper end.

The upper end of a brace according to the present invention may act as adriving surface for a hammer or other arrangement to drive the beam intothe surface immediately surrounding the pole to be reinstated.Accordingly the upper surface of a brace according to the presentinvention is preferably substantially horizontal in the intendedorientation of use. Preferably an insert or dolly which is constructedwith a head to toe hammer blows is inserted into the end of the tubularmember forming the upper end of the brace.

The components used in accordance with the present invention includingthe beam and the connection means are preferably formed of materialswhich not only have sufficient strength to perform the task required butare also unlikely to be corroded or otherwise degraded rapidly in theprevailing weather conditions. The materials should also preferably notbe such as to establish any form of adverse reaction with the soundtimber of the pole. We have found that a steel beam, preferablygalvanised, and connectors formed of steel or other non-corrodingmetallic components are particularly suitable for use in accordance withthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

To further assist in the understanding of the present invention,particularly preferred embodiments of the invention will now bedescribed in relation to the accompanying drawings.

FIG. 1 is a cut away cross sectional perspective view of a reinstatedpole according to one preferred embodiment of the present invention;

FIG. 2 is a cut away cross sectional perspective view of a reinstatedpole according to another preferred embodiment of the present invention;

FIG. 3 is a cross sectional plan view of a bridging beam according toanother preferred embodiment of the present invention;

FIG. 4 is a side view of a pole reinstated with the bridging beam ofFIG. 3;

FIG. 5 is a side view at 90° to that of FIG. 4;

FIG. 6 is an end view of a bridging beam according to another preferredembodiment of the present invention;

FIG. 7 is a plan view of a transmission arrangement according to onepreferred embodiment of the present invention which may be used inconnection with any of the embodiments disclosed herein;

FIG. 8 is a side view of a backing plate according to one preferredembodiment of the invention which may be used in connection with any ofthe embodiments of the reinstated poles or bridging beams disclosedherein.

FIG. 9 is a cross sectional end view of the plate of FIG. 8;

FIG. 10 is a side view of an alternative preferred form of backing platein accordance with the present invention; and

FIG. 11 is a cross sectional end view of the plate of FIG. 10.

FIG. 12 is a cross sectional end view of a reinstated square poleaccording to an alternative preferred embodiment of the invention.

FIG. 13 is a side view of the reinstated pole of FIG. 12.

FIG. 14 is a side view at 90° to that of FIG. 13.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, a bridging beam 1 according to the presentinvention comprises a sleeve portion 2 for abutting the external surface3 of a pole 4. As clearly seen in FIGS. 1 and 2, pole 4 has beenweakened by decay in the central portion.

Beam 1 includes an external brace 5 to provide additional stability tosleeve 2 and hence to reinstated pole 4.

Brace 5 is referred to herein as an external brace member since it ismounted on the outside of sleeve 2 while the inside of sleeve 2 abutsthe external surface 3 of pole 4.

As best seen in FIGS. 4 and 5, a bridging beam 1 is of substantiallyconstant cross section throughout the major portion of tis length.Bridging beam 1 does not taper for a significant portion of its lengthbut includes a cambered end portion 6 also referred to as sledge end 6at the lower most extremity of beam 1 which is shaped to facilitatedriving beam 1 into the soil immediately surrounding pole 4.

As best seen in FIGS. 3 and 6, sleeve 2 is formed, in the preferredarrangements illustrated, from a single piece of material. Sleeve 2 issubstantially arcuate in cross section in the embodiments shown in FIGS.1 and 6, however in the embodiment shown in FIGS. 2 and 3, sleeve 2comprises a polygonal shaped section. Both the smooth curve and thepolygonal shaped curve of sleeves 2 are complementary to the shape ofthe circumference of the poles being reinstated and in cases where poleshave a more clearly defined and reproducible outer shape, the shape ofsleeve 2 can be adjusted to be complementary thereto.

As clearly seen in FIGS. 4 and 5, sleeve 2 includes apertures 7 throughwhich at least a portion of connection means 8 passes.

As clearly seen in FIGS. 4 and 5, the outer marginal edges of sleeve 2are substantially vertical in use. In the embodiments illustrated inFIGS. 4 and 5, the representative ground line for an installed pole isindicated by dotted line G-L. As clearly illustrated in FIGS. 4 and 5, agusset 9 is provided along a portion of both outer marginal edges ofsleeve 2. As clearly seen from FIGS. 3 and 6, gusset 9 is in the form ofan extension of the outer edge of sleeve 2 which projects outwardly fromthe pole. In the embodiment illustrated in FIG. 6, the gusset is formedintegrally with the sleeve although a separate element attached tosleeve 2 such as by welding is used in the embodiment of FIG. 3.

As best seen in FIGS. 4 and 5, gusset 9 extends longitudinally of theouter marginal edges of sleeve 3 for a sufficient length to bridge thedecayed area of pole 4.

In the embodiment illustrated in FIG. 3, gusset 9 extends substantiallynormally to the plane of sleeve 2 at the join 10 between gusset 9 andsleeve 2. In the embodiment illustrated in FIG. 6, gusset 9 is formedintegrally with sleeve 2. Although gusset 9 as shown in FIGS. 3 and 6 isin both cases arranged substantially normally to sleeve 2, other anglesare also envisaged within the scope of the present invention.

The embodiments shown in FIGS. 3 and 6 show two different forms ofexternal brace 5 in accordance with the present invention. Other formsof brace 5 are also envisaged within the scope of the invention.

In the embodiment shown in FIG. 3, brace 5 is in the form of an externalchannel positioned outwardly of sleeve 2 and permanently mounted thereonby welds 11 although other forms of attachment are also envisaged withinthe scope of the present invention.

The construction and arrangement of brace 5 in each case imparts anadded stability to sleeve 2 in a direction tangentially to sleeve 2 asindicated by the double headed arrow T as well as normally to the sleeveand hence radially of the pole as indicated by the double headed arrowR. By imparting stability to the sleeve in both directions T and R, thebrace 5 effectively provides stability in other directions also.

In the embodiment shown in FIG. 3, channel shaped brace 5 is in the formof a U-shaped channel having a pair of arms 12 and 13 connected by domedweb portion 14. The brace 5 is mounted on the outer surface of sleeve 2at the speed locations indicated by welds 11. Although sleeve 2 is in asingle unitary member, it can be appreciated that the portion of sleeve2 which extends between welds 11 acts as a spreader for brace 5 therebyacting to maintain the integrity of brace 5 under load. In theembodiment shown in FIG. 3, the brace 5 together with the spreaderportion of sleeve 2 effectively form a box section with the sleeve 2providing additional strength to the beam 1.

In the alternative arrangement shown in FIG. 6, arms 12' and 13' arewelded together at apex 14' of brace 5. In that arrangement, there is anadditional strengthening member 15 which extends radially of the polebetween the outer surface of sleeve 2 and apex 14'. When strengtheningmember 15 is employed this provides additional strength to beam 1.

As clearly seen in FIGS. 1 and 2 bridging beam 1 is connected to thepole 4 by connecting means 8. Connecting means 8 is in the form ofthreaded connector 16 which extends through pole 4. Threaded connector16 is in the form of a bolt having a head 17 at one end. In thearrangement of FIG. 1 head 17 is captured in frusto-conical end cap 18whereas the other threaded end 19 of connector 16 threadedly engages endcap 20.

As clearly seen in FIGS. 1 and 2, connector 16 extends substantiallyacross the centre of pole 4. End caps 18 and 20 each contain a centralbore which in use is aligned substantially with the central boreextending through the pole to receive threaded connector 16. End caps 18and 20 each have an outwardly extending lip 21 arranged to extend overthe marginal edges surrounding an aperture 7 in sleeve portion 2. Ashank portion 22 depends from outwardly extending lip 21 whereby to passthrough the aperture in sleeve 2. Shank portion 22 merges withfrusto-conical end portion 23 which nestles into a correspondingfrusto-conical countersink hole in pole 4.

As clearly seen in the drawings end caps 18, 20 and the other end capsillustrated include an hexagonal bore useful for receiving acomplementary shaped tool to facilitate tightening of the connectionmeans by rotation of the end cap.

The two alternative forms of backing plate 24 shown in FIGS. 8 through11 vary in size but both are shaped to substantially conform to theexternal surface 3 of pole 4. The backing plate shown in FIGS. 8 and 9is significantly larger than that shown in FIGS. 10 and 11 as anillustration of the differing forms of backing plate which may beutilised in accordance with the present invention. The size and shape ofbacking plate 24 may be varied as known in the art with a view tospreading the load exerted by connecting means 8 over a greater area ofexternal surface 3.

As best seen in FIG. 4, brace member 5 does not extend to the upperextremity of sleeve portion 2. This enables a portion at the upper endof beam 1 to be free of brace 5 and this unbraced sleeve portion issuitable for receiving strapping 25 which passes around pole 4.

In the arrangement shown in FIG. 2, where only one bridging beam 1 isrequired to reinstate the pole, strapping 25 binds the unbraced sleeveportion at the upper end of brace 5 (not shown) and backing plate 24receives the strapping 25 and the other side of pole 4, therebyspreading the load exerted by strapping 25 over a broader area ofexternal surface 3. In the embodiment illustrated in FIG. 2, backingplate 24 is also apertured to receive connecting means 8. In thisarrangement the head 17 of threaded connector 16 is directly mounted onbacking plate 24 via washer 28. In this arrangement the use of an endcap and countersink hole are avoided. The other end of connector 16 ismounted on sleeve 2 via threaded arrangement in end cap 18.

As clearly seen in FIG. 4, the upper end of brace 5 is substantiallyhorizontal in use and may act as a driving surface 26 to beam 1 into theground immediately adjacent pole 4.

As shown in FIG. 7, underground services 26 may be located in aneasement which runs substantially beneath and parallel to overheadtransmission line 27. Such services generally run beside poles 4 andsometimes cross the easement but do not generally do so in closeproximity to neighbouring poles.

If either of the poles 4 shown in FIG. 7 failed, one would expect thatthe transmission lines 27 would prevent the pole from falling in adirection longitudinally of transmission lines 26 which is in thedirection indicated by the double headed arrow R. However, if eitherpole 4 should fail, it would be more typical for the pole to fallsideways, ie. transversely of the transmission lines 27 in the generaldirection indicated by double headed arrow T. It is to be noted fromFIG. 7 that the directions T and R correspond to those in FIGS. 3 and 6.The beam provided by the present invention accordingly can be located asillustrated in FIG. 7 between neighbouring poles 4 while providingimproved support in both the normal and tangential directions indicatedby double headed arrows T and R without being in danger of contactingthe other surfaces by being installed within the casement which would bethe case if beams 1 were installed beside poles 4 at an angle of 90 tothe location shown in FIG. 7. The beams 1 provided in accordance withthe present invention and the method disclosed herein for reinstatedpoles 4 accordingly provides a significant advance over the previouslyknown support members.

In the embodiment shown in FIG. 12, a bridging beam 40 which includestwo elongate flat members 41 joined via the right angled join 42 is usedto reinstate a pole of square or rectangular cross section 43. As in theprevious embodiments, a brace 44 is mounted on the outside of thebridging beam and spans the join 42 between the two elongate flatmembers forming the sleeve of the bridging beam.

The opposite side of the pole is provided with a backing plate 45 whichperforms in similar fashion to the backing plates illustrated in thepreceding embodiments. Both the bridging beam and the backing plate areprovided with a plurality of openings 46 which are used to provideaccess for the connection which attach the backing plate and thebridging beam to the pole in the manner illustrated.

A number of recesses 47 have been drilled in the pole to accommodate theplugs 48 which act in concert with the connection means to secure thebacking plate and the bridging beam to the pole. The backing plate andbridging beam are joined by connection means 49 extending through thepole. The connection means may comprise a bolt 50, nut 51 and washerarrangement 52. These extend through the plugs and the pole to join themand hold them securely in the manner illustrated. It is preferred thatthe bolts be located so that they generally bisect the square orrectangular cross section of the pole being reinstated. Preferably,successive bolts are at 90° to each other.

The plugs may be formed with a circular shaped flange 53 which isadapted to push up against the outer face of the bridging beam andbacking plate when the nut and bolt arrangement is tightened, therebyfirmly securing the bridging beam and backing plate to the pole. Theshaped flange 53 may have a generally "C" shaped profile. The outer edgeof the flange may press against the flat members.

The brace 44 may be formed with a shoe or slipper 54 shaped to force thebeam close to the pole when it is pushed in next to the pole as it isbeing reinstated.

As for the other embodiments, whilst FIGS. 12 to 14 illustrate abridging beam in association with a backing plate, it is also possibleto replace the backing plate with a second bridging beam of similardesign to the first. Such constructions may be favoured when the degreeof additional strengthening required for the pole is relatively high.

While it has been convenient to describe the invention herein inrelation to particular preferred embodiments, it is to be appreciatedthat other constructions and arrangements are also considered as fallingwithin the scope of the invention. Various modifications, alternations,variations and/or additions to the constructions and arrangementsdescribed herein are also considered as falling within the ambit andscope of the present invention.

We claim:
 1. A bridging beam for bridging a weakened area of a pole toreinstate the pole said beam including a sleeve for abutting theexternal surface of the pole on an inner surface of said sleeve and anexternal brace extending outwardly from an outer surface of said sleeveportion, said brace being constructed to brace the sleeve in radial andtangential directions relative to the sleeve, said brace being formed asan elongate tubular box section.
 2. A bridging beam according to claim 1wherein the brace is mounted on the outer surface of the sleeve at twospaced locations.
 3. A bridging beam according to claim 2 wherein thesleeve portion between the two spaced locations acts as a spreader forthe brace whereby the brace forms a tubular member with the sleeve.
 4. Abridging beam according to claim 3 wherein the outline of said tubularmember is selected from one of the group comprising generally semioval,semicircular, box, triangular or polygonal or a combination thereof. 5.A bridging beam according to claim 3 wherein the tubular member includesan elongate strengthening member extending between the brace and thesleeve.
 6. A bridging beam according to claim 3 wherein a singleelongate brace is mounted on the sleeve said single elongate braceincluding mounting elements adapted to facilitate mounting of saidelongate brace at two spaced locations on the sleeve.
 7. A bridging beamaccording to claim 6 wherein said mounting elements comprise a pair ofintegral arms extending lengthwise along both sides of the brace.
 8. Abridging beam according to claim 1 wherein said sleeve has an upper endand a lower end, said brace extending lengthwise along said sleeve andterminating at one end at a position such that it leaves the upper endof said sleeve free of said brace and said one end of said braceprovides a driving surface for facilitating driving of the bridging beaminto the ground surrounding the pole to be reinstated.
 9. A bridgingbeam according to claim 1 wherein said sleeve is formed from a singlepiece of material, the shape of said sleeve being substantiallycomplementary to the shape of the circumference of the pole beingreinstated and spanning more than 10% of the circumference of said pole,said sleeve including one or more gussets extending at an angle to andlengthwise along the sleeve.
 10. A bridging beam according to claim 9provided with two gussets extending at an angle to and lengthwise alongboth sides of said sleeve over at least 10% of the length of saidsleeve, said gussets being integral with or welded to said sleeve.
 11. Abridging beam according to claim 4 wherein said sleeve has an upper endand a lower end, said brace extending lengthwise along said sleeve andterminating at one end at a position such that it leaves the upper endof the sleeve free of said brace and said one end of said brace providesa driving surface for facilitating driving of the bridging beam into theground surrounding the pole to be instated.
 12. A bridging beamaccording to claim 1 wherein the brace is constructed to brace thesleeve in such a manner that the sleeve provides resistance to twistingof the pole about the longitudinal axis of the pole.
 13. A bridging beamaccording to claim 1 wherein the sleeve includes a pair of elongate flatmembers with a right angle lengthwise join therebetween and the brace isjoined to each flat member and spans the right angle join.
 14. Abridging beam according to claim 13 wherein the flat members integrallyform part of a single sheet of metal or are welded together at the rightangle join.
 15. A method of reinstating a pole including driving abridging beam according to claim 1 into ground surrounding said pole andsecuring said bridging beam to said pole.
 16. A method according toclaim 15 wherein connector means extending from said bridging beam tobacking means located on the opposite side of said pole are provided tosecure said bridging beam to said pole.
 17. A method according to claim16 wherein said connector means include threaded connectors extendingthrough the pole and said backing means comprise a backing plate or asecond bridging beam substantially the same as said first bridging beam.18. A method according to claim 17 wherein said pole is provided withcountersunk holes for receiving end caps which are mounted in mountingholes provided in said first bridging beam and said backing means, saidend caps extending into said countersunk holes, and opposed pairs of endcaps mounted in said bridging beam and said backing means are joined bysaid threaded connectors to secure said bridging beam to said pole. 19.A method according to claim 18 wherein said end caps are substantiallyfrusto-conical in shape and have a central bore for receiving saidthreaded connectors and said threaded connectors each comprise a bolthaving a head at one end and a threaded shaft at the other.
 20. A methodaccording to claim 19 wherein a preservative cream is inserted in to thecountersunk holes prior to insertion of said end caps thereinto.
 21. Amethod according to claim 16, wherein said brace has an upper end andlower end, and said brace extends lengthwise along said sleeveterminating at one end at a position such that it leaves said upper endof said sleeve free of said brace to provide a driving surface, drivingsaid bridging beam into the ground surrounding said pole via saiddriving surface, securing said bridging beam to said pole by strappingpassing around said upper end of said bridging beam and said pole andsecuring connector means extending through said pole to said bridgingbeam and to backing means provided on the opposite side of said pole.22. A pole and wire assembly including a plurality of in line polesarranged to support one or more wires extending therebetween, wherein atleast one of said poles has been reinstated in accordance with themethod of claim 15 and the brace of the bridging beam used to reinstatethe pole extends into the region enclosed between straight parallellines tangentially touching opposite sides of adjacent poles.
 23. A poleand wire assembly including a plurality of in line poles arranged tosupport one or more wires extending therebetween, wherein at least oneof said poles has been reinstated in accordance with the method of claim21 and the brace of the bridging beam used to reinstate the pole extendsinto the region enclosed between straight parallel lines tangentiallytouching opposite sides of adjacent poles.